Press of the compressed-air type for the casting of precious metals



0a. 20', 1925. 1,558,201 R. V. NINCK mass OF THE COMPRESSED AIR TYPE FOR THE CASTING 0F PRECIOUS mauns Fil'ed Feb. 29. 1924 s Sheets-Sheet 1 Oct. 20, 1925 R. v. NINCK PRESS OF THE COMPRESSED AIR TYPE FOR THE CASTING OF PRECIOUS METALS 3 Sheets-Sheet 2 Filed Feb. 29, 1924 Oct. 20, 4

R. V. NINCK AIR TYPE FOR THE CASTING OF PRECIOUS METALS PRESS OF THE COMPRESSED 3 Sheefs-Sheat 3 Filed Feb. 29, 1924 i cinerated 2h,

RENE VIGTGR N110" CK, OE NICE, FRANCE.

My invention relates to presses which are employed in the oi moulding on the lost war; prii'iciple wherein the melted metal is cast in the mould under pressure, for the obtainment of dental pieces, goldsmiths work and the like objects.

Various means have been employed in the lost was: process whereby the metal is torced into all parts oi the mould. The process termed sling process or centrifugal process which is still in use at the present time by dentists and goldsmiths requires considerable skill and is attended with an unduly rapid cooling, besides producing irregular results. Presses of known types are employed which operate by compressed air troni an outside source (pumps, reservoirs, conduits and the like), but such apparatus require an installation of some size; the exoense ot' the plant is considerable and the 1:; erruiou becomes more di'l'licult because various cocks or valves are to be manipulated and a pressure-gauge must be observed: the diiliculties are her increased i the necessity of operating in a very rapid manner in order to obviate the drawbacks due to cooling. @ther apparatus make use of presses ot' the steam pressure ty; e, app ying moistened asbestos upon the preliminarily heated mould but such presses are inconvenient because the pressure is abruptly produced, and it is impossible or at least very difficult to limit the pressure, resulting in the distortion of the mould, the er nsion oi the melted metal, the formation or" burrs and blisters, while on the other hand the cooling is too rapid, so that the metal may be solidified before the moulding operation completed.

The invention relates to a press of the known seltcoutained type which comprises a lever-controlled air prunp which is so di posed that when a part of the pump serving a closing plate (e. the bottom of the pump cylinder) is applied upon the envelope oi the mould in order to close the same, it is the following is a speciiica THE CASTIIJG F PRECIOUS METALS.

Serial No. 695,947.

imply necessary to operate the said lever SO as to compress the air in the pump andl'o deliver it directly into the mould through a suitable aperture in th elosin plate.

My 'nvention has for its obyeet to provide pe which is readily manipucan be operated by any person by its entirely automatic action, and of very simple construction and etured at comparatively small expense improved press is chiefly characterized in hot the relative displacement of the closing plate of the pump and th mould as well as the operation of the pump are obtained by means ot a single operating lever, in such manner that the continuation of the movement of closing the mould will act to set up the pressure within the said mould, or otherwise stated, the closing plate of the mould is combined with a device controlling the other part of the pump, so that the displacement of the control element which produces the relative movement between the,

mould and its closing plate will in the first place press the said plate upon the top of the mould in order to close the same, and will then compress the air within the body of the pump n order to deliver the air into the mould. The pump cylinder is for instance movable upon its slides so that the bottom oi the same shall be applied against,

the envelope oi"? the mould, with interposition of a packing member, and the displacement oi the said cylinder will no longer be effected ly positive control, but through the intermediary of a spring interposed between the same and a piston-controlling lever, whereby the descent of the lever will bring the said cylinder upon the mould at a pressure which is limited by the spring, and will then displace the piston in its cylinder, compressing the spring and at the same time delivering the compressed air into the mould.

The invention further relates to various detail arrangements and chiefly for regulating the air pressure, and also for the purpose oi facilitating (and if necessary rendering automatic) the extinction of the blowpipe iet employed for the heat ng of the mould.

The appended drawings show by way of example an embodiment of the invention. Fig. 1 is a general sectional view of the apparatus upon the longitudinal axis; Fig.

ill

2 is a transverse section on the line Il'll, Fig. 1, and Fig. '3 is a plan view.

The apparatus comprises a ribbed base plate 1, as above explained, having formed therein a cylindrical cavity 2 having the centre line OO and containing the filling rings "3, 3 of different diameters, whereby various envelopes t moulds having difierent diameters (such M shown in dotted line) can be disposed in the same upon a packing disc 4, in the known manner. To the said base plate are secured two guide rods -5 having a diametrically opposite position with respect to the centre line Q-O and servim as guides for the pump cylinder G which is sl'idable thereon by means of the lugs G. The said cylinder is held in position upon said guide rods by the set screws 7. The cylinder is closed by a cover '8 which is pierced with an aperture for the inlet of air which is withdrawn from the exterior; said cylinder co-operates piston made of pressed leather 9 which is mounted at the end of a rod 10 pivoted at ii to the operating lever 12 having the handle 12, said lever being pivoted by u'leans oi the link 13 to the fixed point 14.

The pivoting arrangement 1% comprises a fork 15' disposed at the end of a rod 15 which is slidable in a socket 1G bolted to the base plate 1, and which may be secured in position in said socket by the set screw 17, whereby the height of the pivoting point 1% above the base plate can be varied, according to the height of the envelope oi the mould. A spring 18 abuts iectively against a shoulder on the piston rod 10 and the cylinder cover 8, so that when the said cylinder is held in the raised position by means of the screw 7, the lever 12 will be maintained in the raised position, Fig. 1.

The bottom of the cylinder 21 constitutes a closing plate for the envelope of the mould, and to this effect it is ribbed at the bottom in order to copper-ate with a plastic disc which forms a fiuidtight joint with the edge 7" of the envelope M of the mould. The bottom p is pierced with a central orifice 19.

It is observed that by lowering the handle 12 (after disengaging the set-screw T) the end p of the cylinder is brought upon the edge r of said envelope, thus forming a tight joint. But when this motion is continued, the piston 9 will move within the cylinder G and consequently while the plate p closes the mould with a force delcrmined by the compression spring: 18, the compressed air is torced by the piston through the aperture 15) into the mould whereby the latter shall be entirely filled with the metal. The cover 8 of the cylinder is provided with a stop-plate 20 mounted thereupon by means of the screw 21 and pivoting upon the said screw; a spring 22, Fig. 3, consisting for examule ot a spring strip secured to the screw 21 and to a screw 23 mounted upon said cover, acts by its outer end 24- upon the edge of the stop-plate 20 so as to urge the plate against the piston rod 10 whereby it is made to co-operate with the saw-toothed portion 25 termed upon the said rod. The said plate can be disengaged from the piston by means of the small button 26 mounted upon the plate. The initial position of said piston in its cylinder :an thus be varied so as to regulate the length of the remainder of the stroke after the end of the cylinder 7) comes into contact with the mould envelope M, and hence to regulate the air pressure at the end of the stroke. The said blade or stop-piece also serves to lock the piston with reference to the cylinder at the end oi" the compression stroke, so that when the said lever has been lowered to the maximum, it suiiices to screw in the screw 7 in order that the said cylinder shall be held against the mould and that the pressure shall be maintained therein, without being obliged to maintain the lever by hand.

It will be observed that the spring 18 SQI'VGS t0 811$ll18 the necessary pressure 01 the fluidtight action of the joint during the movement of the piston in the cylinder, in spite of the action of the compressed air exercised below the plate p within the mould envelope M.

The gas burner 27 provided with the connecting nipples 28 is pivoted to a rod 29 slidable in a socket 30 and held in position by the set screw 31, the socket 30 is secured to the base plate 1 by a nut screwed upon the lower screwthreaded end of the socket which traverses a radial slot 32 in the said plate. In this manner, the spacing of the said burner as well as its height above the mould envelope can be regulated at will with reference to the height of the mould by displacement of the socket 230 in its slot and of the rod 29 in its socket 230.

According to the invention, the pivot of the burner 27 upon the rod 29 i'orms a valve whose drum is constituted by the tube of "the burner and the outer part 3% by a supporting spindle 29, so that it will suffice to lower the burner by hand upon its pivot in order to cut of? the gas supply and thus to extinguish the burner, while at the same no one allows a tree passage for the said liuder. The device can even be so comed that the contact between the lower ot the id cylinder against the burner shall autou .lically eilect the rotation and consequent extinction of the latter.

it will be observed mat the burner is adjustable in the socket 30 by means of the set screw 'll and it will be seen that the said urner can be adjusted with respect to v: ous heights of moulds. .ln order to insure the automatic movement oi the gas lll) Li "J burner away from the mould and the consequent extinguishment of its flame, it is only necessary to raise the burner a suiiicient height above the top of a mould so that as the piston cylinder moves downward it will engage the burner, to rotate it downwardly on its axis to clear the top of the mould and extinguish the flame. This is obviously an important feature since the construction permits of the automatic re moving of the burner and at the same time cooperates with the valve construct-ion provided to extinguish the flame.

The operation is as follows:

The envelope M and the mould are placed in position after the usual heating operation and after the removal of the rings 3 having smaller diameter; the height of the pivot 14 and the height of the burner are respectively adjusted by the screws 1? and according to the diameter and height of the mould, and the initial position of the piston in its cylinder is determined according to the desired pressure by a partial lowering of the lever 12. After these operations have been performed, the metal which is to be cast in the mould is heated by the burner in the known manner, and when the stated temperature is attained the screw 7 is unscrewed, the handle 12' is lowered to the maximum by a single movement and the screw 7 is screwed up. The cylinder closes the mould in an automatic manner mo ing aside and extinguishing the burner, and compressed air has been admitted to the interior of the mould. In this manner the operation is quite instantaneous; no cooling effect is to be apprehended and the pressure is limited exactly to the desired degree; the control is very simple and entirely automatic, and the operation can now be performed by an apprentice or a person who is entirely unskilled in the art. On the other hand, the apparatus is portable, self-contained and independent of all outside sources or compressed air; its construction is simple and substantial, resulting in a comparatively inexpensive construction.

Obviously, the form of construction hereinbeiore described is given solely by way of example, and it is susceptible of all desired modifications without departing from the principle of the invention; for example, the fitting of the said cylinder upon the mould in order to close the same may be controlled by a lever which is independent of the lever controlling the piston in order to obtain the pressure, but the operation will be less rapid and convenient. Instead oi using a fixed mould and a movable cylinder, the inverse disposition may be employed; instead of constituting the closing plate 7) by the bottom of the cylinder, it

may be constituted by the piston itself, and

in this case the control lever is connected witli the cylinder; the pressure obtained at the end ot the stroke need not be regulated by the variation of the initial position ot the piston in the cylinder, but it may be regulated by varying the final position of the piston in the cylinder, using for the purpose the ratchet connection between the ylinder and the piston rod. The bottom part n has shown integral with the said c linder, but in actual construction it preferably consists oi an. interchangeable base, so that its diameter may be varied according to the diameter of the envelope lL-l.

Claims 1. A press tor casting; metals under pressure in moulds of the lost wax type, comprising a pump cylinder movable upon guides whi h are vertical in principle, the bottom of said cylinder being: aperturezl near the centre and constitutii the closinr plate of the mould casing, a piston provid ed with a rod and movable in the said cylinder, means for controlling the said pis ton through the medium of its rod and u spring interposed between the said controlling means and the pump cylinder in order to apply the said plate upon the mould with elastic force and to subsequent allow the piston to move in the said cylinder under the positive action of said controlling means, with compression oi the said spring, ratchet means provided between the said pump cylinder and the piston rod whereby the cylinder may be secured to the piston when in any given position and at any suitable moment of the operation.

2. A press for casting metals under pressure in moulds of the lost wax type, comprising; a pump cylinder movable upon guides which are vertical in principle, the bottom of said cylinder being epertiu'ed near the centre and constituting the closing plate of the mould casing, a piston provided with a rod and movable in the said cylinder, means for controlling the said piston through the medium of its rod, and a spring interposed between the said controlling means and the pump cylinder in order to apply the said plate upon the mould with elastic force and to subsequently allow the piston to move in the said cylinder under the positive action of the said controlling means, with compression of the said spring, a set screw being disposed upon the said cyl inder whereby the latter may be secured at any suitable point upon its guides.

3. A press for casting, metals under pressure in moulds ot the lost wax type, comprising a pump cylinder movable upon guides which are vertical in principle, the bottom of said cylinder beingapertured near the centre and constituting the closing plate of the mould casing, a piston provided with a rod and movable in the said cylinder means for controlling the suit, oist '1 adapted to be engaged by said pump and interposed between the said means and the pump c chnder in order to apply the said. plate r-pon the mould witu the positive means with wmpression oi the said sprii ratchet means being disposed between said pump cylinder and the piston whereby the cylinder uni be s cured to piston wl en in any given pc. any suitable moment of ii .0 operation, a i screv: being digposed upon the said c whereby the latter may be secured at suitable point upon its guides.

4. in an apparatus of the cla describw a pump for supplvin air to s 7 id pump \onuirisii a cylinder am pston, means forn'ied on he stem of pis'lon for rooperating with means 'l'ormed on said cylinder tor adjusting the relationship the cylinder and piston whereby the amount of air supplied to said l'iasli may be aried.

5. in an apparatus or the class describec a flash, :1. pump for supplyin air to said llaslr comprising a cylinder id :1 piston, ratchet teeth i'ormed on said piston. a ratchet member formed. on saizil cylinder or cooperating with said teeth \vh I amount oi air delivered to said has i may be varied.

G. In an apparatus of the class described, a flask, a pump for supplying air thereto comprising a cylinder and piston, means iOlll'lOd on said cylinder and piston for regulating the amount of air supplied to said flask, and a heating member for said flask adapted to be moved to inoperative position when said pump is operated.

7. In an apparatus of the class described, a flask, a pump for supplying air thereto comprising a cylinder and piston, means formed on said cylinder and piston for regulating the amount oi air supplied to said flask, an adjustably mounted blow torch moved to inoperative position.

8. In an apparatus of the class described, a base, a flask mounted thereon, an operating member pivot-ally and adjustably mounted on said base, a piston operable by said operating nien'iber. and a cylinder resiliently "unted on said piston whereby movement the operating member will serve to dis charge air iron: said cylinder into said flash.

El, ln an apparatus of the class described, base, a ti 1 mountedthereon, an operating member p \otally and adjustably supported by said base a piston connected to said operating member, and a cylinder mounted on said piston and adjustable with relation thereto whereby when said member is operated the cylinder closes the open end of said flask and the amount of air supplied may be regulated.

10. in an ap mratus of the class described, a base, a pump mounted for movement on said base and having a cylinder and piston, said pump being adapted to form a closure for the mould and such closure portion having an opening formed therein, means for adjusting the position of the pump with respect to said base, a spring acting between the cylinder and thepiston, the piston having a serrated portion and the cylinder a ratchet whereby the piston and cylinder may be adjusted with relation to each other, to vary the pressure in the mould, a single operating lever for moving said pump to close the mould and for actuating the piston to force air into said mould, and a burner adjustably and pivotally mounted on said base and having a "fuel valve actuated by movement about its pivot, said burner being adapted to lie in the path of movement of the pump whereby as the pump descends to close the mould, the burner will be automatically moved away from the mould and about its pivot to extinguish the flame.

In testimony whereof I have hereunto set my hand.

RENE V ICTOR NINCK. 

